The present invention relates to a sensor element having a memory for abnormal changes of the incident light intensity.
The invention is based on the following consideration: In a number of cases it would be advantageous to have available a sensor element which has a "memory" for abnormal changes of the incident light intensity. With such a sensor element, a light control, for instance, could be realized which can be switched on or activated by a light flash and subsequently keeps, for instance, the light of an illuminating unit at a given value. A further application of such a sensor element would be a light control unit which, after a light failure, does not "start again" automatically but makes provision that after an unintended extinction of the light, the light is regulated to the previously set value only if, for instance, an operator gives a specific command therefor.
Such light control circuits can, of course, be realized with sensor elements which are followed by a logic or microprocessor circuit. A sensor element of simple design with a memory for abnormal changes of the incident light intensity, however, is not known. Such a sensor element, however, would be desirable especially if a number of such sensor elements is to be arranged in an array in order to take care, for instance, of complicated monitoring functions. It goes without saying that it is not tolerable for cost reasons to provide a microprocessor for each sensor element.